package org.bouncycastle.jce.provider;

import java.security.InvalidKeyException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.interfaces.DSAPrivateKey;
import java.security.interfaces.DSAPublicKey;

import org.bouncycastle.crypto.params.AsymmetricKeyParameter;
import org.bouncycastle.crypto.params.DSAParameters;
import org.bouncycastle.crypto.params.DSAPrivateKeyParameters;
import org.bouncycastle.crypto.params.DSAPublicKeyParameters;

/**
 * utility class for converting jce/jca DSA objects objects into their
 * org.bouncycastle.crypto counterparts.
 */
public class DSAUtil {
    static public AsymmetricKeyParameter generatePublicKeyParameter(
            PublicKey key) throws InvalidKeyException {
        if (key instanceof DSAPublicKey) {
            DSAPublicKey k = (DSAPublicKey) key;

            return new DSAPublicKeyParameters(k.getY(), new DSAParameters(k
                    .getParams().getP(), k.getParams().getQ(), k.getParams()
                    .getG()));
        }

        throw new InvalidKeyException("can't identify DSA public key: "
                + key.getClass().getName());
    }

    static public AsymmetricKeyParameter generatePrivateKeyParameter(
            PrivateKey key) throws InvalidKeyException {
        if (key instanceof DSAPrivateKey) {
            DSAPrivateKey k = (DSAPrivateKey) key;

            return new DSAPrivateKeyParameters(k.getX(), new DSAParameters(k
                    .getParams().getP(), k.getParams().getQ(), k.getParams()
                    .getG()));
        }

        throw new InvalidKeyException("can't identify DSA private key.");
    }
}
